Power bond



April 18, 1939- c. A. FORSSELL 2,154,674

POWER BONDS Filed March 20, 1956 Patented Apr. 18, 1939 UNITED STATES PATENT OFFICE POWER BOND Carl Abraham Forssell, Stockholm, Sweden Application March 20, 1936, Serial No. 69,963 In Sweden March 23, 1935 11 Claims. (01. 20-92) The present invention relates to a power-bond Two embodiments of the invention are illusbetween a mounting, furniture, or strap of iron trated by way of example in the accompanying or other metal and wood or the like which powerdrawing, in which bond comprises spikes or nails forced into the Figure 1 is a plan View and Fig. 2 a longitudinal Wood through holes in the mounting, furniture section of a device according to the invention, or strap (hereinafter referred to as the furni- Figs. 3 and 4 are a plan view and a longitudinal ture). section respectively of a modified form of the The main object of the invention is to provide invention, bonds of the kind referred to, in which the spikes Fig. 5 is a cross-sectional view along line I-I are bending-resistibly joined with the furniture. of Fig. 3, and 1;:

The simplest way of effecting the bending- Figs. 6 and 7 represent a side elevational view resistant bond according to the invention is to and a bottom plan View, respectively, of the form force the spike or nail or the head thereof through of spike seen, for example, at the left hand end a hole in the mounting, furniture or strap by of Fig. 4 in front elevation.

means of power. The head or shank of the spike Referring to Figs. 1 and 2 the reference numer- {L5 or nail may have a form differing from that of ah I and 2 indicate wood elements connected the hole so as to cause a deformation of any kind by means of the iron strap 3 which is connected of the spike or of the material in the furniture. to the wood element 2 by means of a spike or According to essential features of the invention nail 4 having a edge-shaped head 4 and a the tapering, conical, wedge-shaped, cylindrical, shank 4 The strap 3 is connected to the wood- 20 or square spike or spike head is forced through a element l by means of the spikes 5 and I. These tapering, conical, wedge-shaped, cylindrical or spikes are of the same kind as the spike 4 but in square hole in the furniture. If both the spike distinction therefrom they have a we d n J' head and the hole in the furniture are conical e and 8 respectively between the spike head and or wedge-shaped, they may have different top the strap.

angles. In Figs. 3-5 the wood elements 9 and it are According to another feature of the invention connected by means a iron strap This the spike or spike head or the hole of the furnistrap has on a part of its length a double layer ture or both have longitudinal grooves or ribs 12 para l to e iron strap l I a connected adapted to serve the clamping of the spike or thereto by l tu at d P t II t ,30 spike head in the furniture. Such longitudinal the remaining part of its length the strap II has grooves or ribs may be present on a cylindrical a double layer in the form of a blunt cone [3.

or otherwise shaped spike head forced by power The spikes l4 and I5 are forced through holes in in a cylindrical or conical hole of the furniture the strap II and in the double layers [2, and

of iron. The head may have the same or a e ag b th of them y their -S p greater cross-sectional size than the adjacent heads. The spike I6 is forced through holes in portion of the spike shank. the strap II and the cone l3 in the same way, According to a further feature of the invention av g engagement between t W d -s ap d the bending-resistant bond between the spike h ad a d b f the cone ay r h sp k s ,1 O and the furniture may be obtained by a welding may have an additional strike-head 20 formed joint applied therebetween after the spike has integral With the Ordinary d s S wn at been forced into the hole. Such a welding joint spike in Figs. 3 a

may also be present at the same time as a device It is to he noted that the spikes 5 d T referred to above and adapted to efiectabendingin Fig. 1 and the Spikes i5 d t in Fig. 3

resistant bond between the spike and the furnia shown by indi at n their t only in the View ture of iron. in question, and that all of the spikes in the According to a still further feature of the in- Various embodiments comprise, like the p e vention the bending-resistant bond may be headahd a integral s ank.

strengthened by assembling the furniture, at y Constructing the spike bond as described least at the spike hole, from two layers spaced and shown in the drawing t e advantage is 50 apart, in which case the spike engages both of obtained that the effective line of the force said layers at the same time. Such a simultanetransmitted y h pik m the Wood element ous engagement of the spike with both layers to the iron furniture need not be directedas may be obtained by forcing the spike or its head in an ordinary bond of said type-through that by power through either or both of the layers. surface of the spike abutting against the furni- 55 ture but is displaced to the interior of the wood element. This follows since the bending moment at that section of the spike which abuts the iron strap results in the production of a lever arm for the shearing force at said section, causing said shearing force to act as if displaced to the interior of the wood element. Therefore, the pressure per unit of surface in the hole-edge between the spike and the wood is a minimum, and as a result the joint will have a maximum of weight carrying capacity for a predetermined spike.

Tests using 6" spikes having a shank as an ordinary 6" oak-spike but having a wedge-shaped head of a suitable form and a wedge-angle of about 10 have resulted in a weight carrying capacity per spike of up to 1800 kg. forcing, the spikes into cylindrical holes made in a furniture plate of 6 mm. thickness. Up to about of said load the movements between the wood and the furniture-iron were very small. As a result of parallel tests using similar spikes, the head of which was to full strength welded to a similar furniture-plate the movements as well as break loads were substantially the same for both of them. The provision of a wedge-shaped square spike-head in a cylindrical hole in the furnitureplate thus utilizes the spike completely and causes no materially greater cost than an ordinary oakspike.

Though the invention is referred to above in connection with a bond between furniture of iron and a wooden element, it is self-evident that it may also be applied to bonds between elements of other material such as furniture of other metal on one hand and elements of hardly pressed fibrous material or the like on the other hand.

What I claim is:

1. A connection of the type stated comprising an element of wood or the like; a piece of metal furniture having holes therethrough; and spikes, having head portions at least parts of which are of greater width than corresponding parts of said holes, forced through said holes and into said element; said spikes being united to said furniture by deformation of the metal thereof due to the forcing of said head portions into the furniture.

2. A connection as claimed in claim 1, wherein said spikes have cross-sections differing from those of the corresponding holes before the spikes are forced into the same.

3. A connection as claimed in claim 1 wherein the portions of said spikes within said holes have cross-sections differing from the initial crosssections of the corresponding holes.

4. A connection of the type stated comprising an element of wood or the like, a piece of metal furniture having holes therethrough, and spikes forced through said holes and into said element, said spikes having outer end portions differing in cross-section from the initial cross-sections of the holes in said furniture, whereby the metal of said furniture is deformed as the spikes are forced therethrough.

5. A connection as claimed in claim 4, wherein the cross-section of the end portions of said spikes differs in shape from the initial crosssections of the corresponding holes.

6. A connection as claimed in claim 4, wherein said holes are initially of circular cross-section, and the ends of said spikes have a polygonal cross-section.

'7. A connection as claimed in claim 4, wherein said outer end portions of the spikes taper with respect to the corresponding holes in said furniture.

8. A connection as claimed in claim 4, wherein said outer end portions of the spikes have a transverse width not less than that of the inner end portions that enter said element.

9. A connection as claimed in claim 4, in combination with welds between said furniture and the spikes.

10. A connection as claimed in claim 4, wherein said furniture comprises a piece of member having spaced sections through which alined pairs of holes extend to receive the spikes.

11. A connection of the type stated comprising an element of wood or the like, a metal strap having holes therethrough, and. spikes forced through said holes and into said element, said spikes having outer heads tapering outwardly at an angle in excess of that of said holes, whereby the metal of the spike heads and of the strap is deformed to form a bending-resistant bond between the spikes and the strap when said spikes are forced into said holes of the strap.

CARL ABRAHAM FORSSELL.

CERTIFICATE OF CORRECTION.

Patent No. 2,1 5L 67h. Y April 8 9 59.

CARL ABRAHAM FQRSSELL. It is hereby certified t t error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, second column, line 56, claim 10, for "furniture comprises apiece of member" read piece of furniture comprises a member; and that the said Letters Patent should be read with thiscorrection therein that the same may conform to' the record of the case in the Patent Office.

Signed and sealed this 16th day of May, A. D 1939.

Henry Van Ars'da'ie (Seal) Acting Commissioner of Patents. 

